“Yesterday, as a result of a server configuration change, many people had trouble accessing our apps and services. We've now resolved the issues and our systems are recovering. We’re very sorry for the inconvenience and appreciate everyone’s patience.”

Downdetector.com, a site that monitors site outages, said the Facebook problem affected parts of the U.S., including the East and West Coast; parts of Europe and elsewhere. Both Facebook's desktop site and app appeared to be affected. Some users saw a message that said Facebook was down for "required maintenance."